Mechatronic · DL501

DL501 mechatronic replacement unit

The DL501 is a 7-speed wet dual-clutch (S tronic), factory code 0B5. Its mechatronic unit combines the hydraulic control and the transmission control electronics in one assembly.

This page covers the typical symptoms, mechatronic faults, fault codes and the replacement units available for the DL501.

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Technical overview

What the DL501 mechatronic does

Like every dual-clutch transmission, the DL501 uses two clutches: one for the odd and one for the even gears. The mechatronic unit actuates the clutches and the gear selectors.

Most faults are linked to hydraulic pressure, solenoids, sensors or the control electronics inside the mechatronic unit.

Replacement units are identified by the OEM part number. Always compare the number on your unit before ordering.

Transmission family	DL501 (7-speed wet dual-clutch (S tronic))
Also known as	0B5
Clutch type	Wet dual clutch
Gears	7 forward
Factory code	0B5

What’s included

Contents of the DL501 mechatronic assembly

The mechatronic assembly combines the hydraulic control unit and the electronic control unit in one housing. A replacement unit is supplied complete, ready to be fitted and adapted to the vehicle.

Hydraulic control unit

Valve body, solenoids and the pressure regulation that operates the clutches and shift forks.

Electronic control unit

The transmission control unit and its sensors, integrated with the hydraulic side in one assembly.

Actuators and sensors

The solenoids, speed sensors and position sensors that let the control unit operate and monitor the transmission.

Housing and connector

The machined housing and the electrical connector through which the unit communicates with the vehicle.

Replacement vs exchange

Two ways to source the DL501 unit

Both options are agreed manually by email. There is no automated core deposit and no online payment.

Replacement unit. You receive a mechatronic assembly and keep your original unit. The simplest option when the original is not serviceable or not required back.
Exchange unit. You receive a unit and return your original. Exchange is agreed by email and is marked on the quotation request form.
Fitment and adaptation. The replacement unit is adapted to the vehicle after fitting, which requires a suitable diagnostic tool. This is confirmed in the quotation reply.

Technical references

DL501 fault codes and repair information

The fault codes and repair pages for this family help confirm which unit is required before you order.

Code	Description	Category	Status
P0700	Transmission control system — malfunction (MIL request)	Transmission control	Review
Description The DL501 transmission control unit stores P0700 when it detects the following condition: Transmission control system — malfunction (MIL request). A general transmission control fault: the control unit has detected a malfunction in the transmission system that is not tied to one specific component. Codes stored at the same time usually point to the actual cause. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Emergency mode Harsh or missing shifts Transmission warning light Possible causes Faults stored in other categories at the same time Power supply or wiring problem Mechatronic unit fault Transmission: DL501 Category: Transmission control Status: Documented — review advised Related components: Transmission control unit (TCU) · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0715	Input/turbine speed sensor A — circuit	Speed sensor	Review
Description The DL501 transmission control unit stores P0715 when it detects the following condition: Input/turbine speed sensor A — circuit. The fault concerns a speed signal. The control unit needs the input (clutch/turbine) and output shaft speeds to control shifts and clutch slip, and stores the code when a signal is missing, implausible or electrically faulty. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Harsh or badly timed shifts Emergency mode Incorrect gear or speed display Transmission warning light Possible causes Faulty speed sensor in the mechatronic unit Wiring or connector fault Metal debris on the sensor or sender wheel Fault in the control electronics Transmission: DL501 Category: Speed sensor Status: Documented — review advised Related components: Input speed sensor · Output speed sensor · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0716	Input/turbine speed sensor A — range/performance	Speed sensor	Review
Description The DL501 transmission control unit stores P0716 when it detects the following condition: Input/turbine speed sensor A — range/performance. The fault concerns a speed signal. The control unit needs the input (clutch/turbine) and output shaft speeds to control shifts and clutch slip, and stores the code when a signal is missing, implausible or electrically faulty. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Harsh or badly timed shifts Emergency mode Incorrect gear or speed display Transmission warning light Possible causes Faulty speed sensor in the mechatronic unit Wiring or connector fault Metal debris on the sensor or sender wheel Fault in the control electronics Transmission: DL501 Category: Speed sensor Status: Documented — review advised Related components: Input speed sensor · Output speed sensor · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0720	Output speed sensor — circuit	Speed sensor	Review
Description The DL501 transmission control unit stores P0720 when it detects the following condition: Output speed sensor — circuit. The fault concerns a speed signal. The control unit needs the input (clutch/turbine) and output shaft speeds to control shifts and clutch slip, and stores the code when a signal is missing, implausible or electrically faulty. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Harsh or badly timed shifts Emergency mode Incorrect gear or speed display Transmission warning light Possible causes Faulty speed sensor in the mechatronic unit Wiring or connector fault Metal debris on the sensor or sender wheel Fault in the control electronics Transmission: DL501 Category: Speed sensor Status: Documented — review advised Related components: Input speed sensor · Output speed sensor · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0721	Output speed sensor — range/performance	Speed sensor	Review
Description The DL501 transmission control unit stores P0721 when it detects the following condition: Output speed sensor — range/performance. The fault concerns a speed signal. The control unit needs the input (clutch/turbine) and output shaft speeds to control shifts and clutch slip, and stores the code when a signal is missing, implausible or electrically faulty. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Harsh or badly timed shifts Emergency mode Incorrect gear or speed display Transmission warning light Possible causes Faulty speed sensor in the mechatronic unit Wiring or connector fault Metal debris on the sensor or sender wheel Fault in the control electronics Transmission: DL501 Category: Speed sensor Status: Documented — review advised Related components: Input speed sensor · Output speed sensor · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0730	Incorrect gear ratio	Gear ratio / gear loss	Review
Description The DL501 transmission control unit stores P0730 when it detects the following condition: Incorrect gear ratio. This is a mechanical plausibility check: the control unit compares the input and output shaft speeds with the ratio expected for the selected gear. The code is stored when the calculated ratio does not match or a gear drops out unexpectedly. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Engine revs flare without acceleration Gear drops out or the transmission stays in one gear Emergency mode Transmission warning light Possible causes Clutch slip Gear disengaging because of a gear selector or shift fork fault Faulty input or output speed sensor Internal mechanical damage (gears, synchronisers, bearings) Transmission: DL501 Category: Gear ratio / gear loss Status: Documented — review advised Related components: Speed sensors · Gear selector / shift fork · Dual clutch · Gear set This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0731	Gear 1 — incorrect ratio	Gear ratio / gear loss	Review
Description The DL501 transmission control unit stores P0731 when it detects the following condition: Gear 1 — incorrect ratio. This is a mechanical plausibility check: the control unit compares the input and output shaft speeds with the ratio expected for the selected gear. The code is stored when the calculated ratio does not match or a gear drops out unexpectedly. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Engine revs flare without acceleration Gear drops out or the transmission stays in one gear Emergency mode Transmission warning light Possible causes Clutch slip Gear disengaging because of a gear selector or shift fork fault Faulty input or output speed sensor Internal mechanical damage (gears, synchronisers, bearings) Transmission: DL501 Category: Gear ratio / gear loss Status: Documented — review advised Related components: Speed sensors · Gear selector / shift fork · Dual clutch · Gear set This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0732	Gear 2 — incorrect ratio	Gear ratio / gear loss	Review
Description The DL501 transmission control unit stores P0732 when it detects the following condition: Gear 2 — incorrect ratio. This is a mechanical plausibility check: the control unit compares the input and output shaft speeds with the ratio expected for the selected gear. The code is stored when the calculated ratio does not match or a gear drops out unexpectedly. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Engine revs flare without acceleration Gear drops out or the transmission stays in one gear Emergency mode Transmission warning light Possible causes Clutch slip Gear disengaging because of a gear selector or shift fork fault Faulty input or output speed sensor Internal mechanical damage (gears, synchronisers, bearings) Transmission: DL501 Category: Gear ratio / gear loss Status: Documented — review advised Related components: Speed sensors · Gear selector / shift fork · Dual clutch · Gear set This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0733	Gear 3 — incorrect ratio	Gear ratio / gear loss	Review
Description The DL501 transmission control unit stores P0733 when it detects the following condition: Gear 3 — incorrect ratio. This is a mechanical plausibility check: the control unit compares the input and output shaft speeds with the ratio expected for the selected gear. The code is stored when the calculated ratio does not match or a gear drops out unexpectedly. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Engine revs flare without acceleration Gear drops out or the transmission stays in one gear Emergency mode Transmission warning light Possible causes Clutch slip Gear disengaging because of a gear selector or shift fork fault Faulty input or output speed sensor Internal mechanical damage (gears, synchronisers, bearings) Transmission: DL501 Category: Gear ratio / gear loss Status: Documented — review advised Related components: Speed sensors · Gear selector / shift fork · Dual clutch · Gear set This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0734	Gear 4 — incorrect ratio	Gear ratio / gear loss	Review
Description The DL501 transmission control unit stores P0734 when it detects the following condition: Gear 4 — incorrect ratio. This is a mechanical plausibility check: the control unit compares the input and output shaft speeds with the ratio expected for the selected gear. The code is stored when the calculated ratio does not match or a gear drops out unexpectedly. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Engine revs flare without acceleration Gear drops out or the transmission stays in one gear Emergency mode Transmission warning light Possible causes Clutch slip Gear disengaging because of a gear selector or shift fork fault Faulty input or output speed sensor Internal mechanical damage (gears, synchronisers, bearings) Transmission: DL501 Category: Gear ratio / gear loss Status: Documented — review advised Related components: Speed sensors · Gear selector / shift fork · Dual clutch · Gear set This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0735	Gear 5 — incorrect ratio	Gear ratio / gear loss	Review
Description The DL501 transmission control unit stores P0735 when it detects the following condition: Gear 5 — incorrect ratio. This is a mechanical plausibility check: the control unit compares the input and output shaft speeds with the ratio expected for the selected gear. The code is stored when the calculated ratio does not match or a gear drops out unexpectedly. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Engine revs flare without acceleration Gear drops out or the transmission stays in one gear Emergency mode Transmission warning light Possible causes Clutch slip Gear disengaging because of a gear selector or shift fork fault Faulty input or output speed sensor Internal mechanical damage (gears, synchronisers, bearings) Transmission: DL501 Category: Gear ratio / gear loss Status: Documented — review advised Related components: Speed sensors · Gear selector / shift fork · Dual clutch · Gear set This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0746	Pressure control solenoid A — performance or stuck off	Valve / solenoid electrical	Review
Description The DL501 transmission control unit stores P0746 when it detects the following condition: Pressure control solenoid A — performance or stuck off. The fault is electrical: the control unit monitors the current and resistance of each solenoid and pressure control valve, and stores the code when it detects an open circuit, a short circuit or a control current outside the expected range. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Harsh or missing gear changes Some gears unavailable Emergency mode, often with only certain gears Transmission warning light Possible causes Faulty solenoid or pressure control valve coil Damaged internal wiring or connector in the mechatronic unit Fault in the valve driver stage of the control electronics Contaminated transmission fluid affecting valve operation Transmission: DL501 Category: Valve / solenoid electrical Status: Documented — review advised Related components: Solenoid / pressure control valve · Mechatronic valve body · Transmission control unit (TCU) This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0810	Clutch position control error	Clutch faults	Review
Description The DL501 transmission control unit stores P0810 when it detects the following condition: Clutch position control error. The fault concerns clutch control: engagement, adaptation, torque limitation or clutch temperature. The control unit compares the commanded clutch position or pressure with the measured value and stores the code when the difference or the adapted value leaves the permitted range. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Judder when pulling away Delayed or harsh engagement Reduced power or emergency (limp-home) mode Transmission warning on the instrument cluster Possible causes Clutch wear or overheating Adaptation values out of range or basic setting not performed Deviation in hydraulic clutch actuation Faulty clutch position or pressure sensor in the mechatronic unit Transmission: DL501 Category: Clutch faults Status: Documented — review advised Related components: Dual clutch · Clutch actuator / pressure control valve · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0841	Transmission fluid pressure sensor/switch A — range/performance	Pressure sensor	Review
Description The DL501 transmission control unit stores P0841 when it detects the following condition: Transmission fluid pressure sensor/switch A — range/performance. The fault concerns a pressure sensor or pressure switch in the transmission. The control unit uses these signals for clutch and system pressure control, and stores the code when the signal is out of range, too low or implausible. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Harsh engagement or judder Emergency mode Pump running unusually Transmission warning light Possible causes Faulty pressure sensor Wiring or connector fault A real hydraulic pressure problem Fault in the control electronics Transmission: DL501 Category: Pressure sensor Status: Documented — review advised Related components: Pressure sensor · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
P0868	Transmission fluid pressure low	Hydraulic pressure	Review
Description The DL501 transmission control unit stores P0868 when it detects the following condition: Transmission fluid pressure low. The fault concerns the hydraulic supply of the mechatronic unit. The control unit compares the required system pressure with the measured pressure and stores the code when the pressure is too low, too high, builds up too slowly, or the pump runs outside its normal operating time. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Delayed gear engagement or loss of drive Pump running unusually often or for a long time Emergency mode or no drive in gear Transmission warning light Possible causes Internal hydraulic leakage (valve body, seals, accumulator) Faulty hydraulic pump or pump motor Low or contaminated transmission fluid Faulty pressure sensor or pressure control valve Transmission: DL501 Category: Hydraulic pressure Status: Documented — review advised Related components: Hydraulic pump / pump motor · Pressure accumulator · Mechatronic valve body This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair
U0101	Lost communication with transmission control module (TCM)	Communication	Review
Description The DL501 transmission control unit stores U0101 when it detects the following condition: Lost communication with transmission control module (TCM). The fault concerns data communication between the transmission control unit and other control units on the powertrain CAN bus. The code is stored when messages are missing or corrupted, or the bus hardware reports an error. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle. Symptoms Gear display missing or flashing Emergency mode Several control units reporting communication faults Transmission not reachable with the diagnostic tester Possible causes Wiring or connector fault on the CAN bus Power supply or ground fault at the control unit Faulty transmission control unit Fault in another control unit on the same bus Transmission: DL501 Category: Communication Status: Documented — review advised Related components: Powertrain CAN bus · Transmission control unit (TCU) · Connectors and wiring This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DL501 quote DL501 repair

All DL501 fault codes →

Price & exchange

DL501 mechatronic unit

Prices are confirmed per request, because the correct unit depends on the transmission generation and the vehicle.

DL501 Exchange available

DL501 DSG mechatronic unit — 4G0927156J

Refurbished DSG mechatronic unit for the DL501 (7-speed wet dual-clutch (S tronic)), OEM part number 4G0927156J (4G0 927 156 J). Supplied as a complete assembly with the integrated control electronics.

Replacement unit EUR 450.00